WaitForND1

class WaitForND1(KPFFunction):
    '''Wait for the ND1 filter wheel (the one at the output of the 
    octagon) via the `kpfcal.ND1POS` keyword.

    Args:
        CalND1 (str): The neutral density filter to put in the first filter
            wheel. This affects both the simultaneous calibration light and
            light which can be routed through the FIU to the science and sky
            fibers. Allowed Values: `OD 0.1`, `OD 1.0`, `OD 1.3`, `OD 2.0`,
            `OD 3.0`, `OD 4.0`

    KTL Keywords Used:

    - `kpfcal.ND1POS`
    '''
    @classmethod
    def pre_condition(cls, args):
        ND1POS = ktl.cache('kpfcal', 'ND1POS')
        allowed_values = list(ND1POS._getEnumerators())
        if 'Unknown' in allowed_values:
            allowed_values.pop(allowed_values.index('Unknown'))
        check_input(args, 'CalND1', allowed_values=allowed_values)

    @classmethod
    def perform(cls, args):
        target = args.get('CalND1')
        timeout = cfg.getfloat('times', 'nd_move_time', fallback=20)
        expr = f"($kpfcal.ND1POS == '{target}')"
        success = ktl.waitFor(expr, timeout=timeout)
        if success is False:
            log.error(f"Timed out waiting for ND1 filter wheel")

    @classmethod
    def post_condition(cls, args):
        timeout = cfg.getfloat('times', 'nd_move_time', fallback=20)
        ND1target = args.get('CalND1')
        ND1POS = ktl.cache('kpfcal', 'ND1POS')
        if ND1POS.waitFor(f"== '{ND1target}'", timeout=timeout) == False:
            raise FailedToReachDestination(ND1POS.read(), ND1target)

    @classmethod
    def add_cmdline_args(cls, parser):
        parser.add_argument('CalND1', type=str,
                            choices=["OD 0.1", "OD 1.0", "OD 1.3", "OD 2.0",
                                     "OD 3.0", "OD 4.0"],
                            help='ND1 Filter to use.')
        return super().add_cmdline_args(parser)